Gynecomasty is the pathological enlargement of one or both mammary glands in men. This disorder is often associated with hyperprolactinemia (excess blood prolactin) and can also be caused by hyperestrogenism derived from a liver disease such as cirrhosis, due to the liver’s inability to metabolize estrogen.
Men undergoing estrogen therapy can develop fat deposits in the form of breast, a process known as pseudogynecomasty, and this frequently develops into a ‘true’ breast, otherwise known as gynecomasty.
The causes of common gynecomasty remain uncertain, although the condition has generally been attributed to high levels of sex hormone binding globulin (SHBG), resulting in lower free testosterone levels or lower response of tissues to them. The condition can also be caused by an imbalance of the effects of estrogen and androgen on the chest, resulting in hormonal increases or breast tissue.
Several conditions can cause gynecomasty by affecting hormone levels. These include: